Tries from Carl Meyer and Wes Cunliffe gave the Steelmen a 3-13 lead at halftime, and despite a Steve Pooler score a Ronny Keynes try secured the points.
At the other end of the table Beddau squeezed past Bridgend Athletic 17-15. Glen Slater scored twice as Beddau cruised to a 14-point lead but Bridgend rallied, with Steve Lewis missing a last minute conversion to secure the draw.
There was another tight game at Blackwood, with Alex Jenkins’ last minute try giving Narberth a 30-28 victory.
Bargoed also won at the death as they beat Cardiff Met 16-17, with the whistle going straight after fly-half Joel Prosser converted Lee Peterson’s try.
There was a more straightforward affair at the Welfare Ground as Newbridge sailed to a comfortable 31-0 win over bottom of the table Bonymaen, with Richard Powell converting all four tries.
Twenty points from Cody Rees gave Llanharan a 34-27 win over Tata Steel, a win which moves them clear of The Saints.
Tata Steel outscored Llanaran four tries to three, with Ross Pritchard going over twice, but the boot of Rees guided Llanharan to victory.
Elsewhere, RCG 1404 beat Tondu easily away from home. RCG scored eight tries, with braces for Hopkins and Hugh Grundy, as the Waterwheelers were easily dispatched.
